Conductive conductivity sensors known from the state of the art-e.g. from EP 990 894 B1-comprise at least two electrodes, which, for measuring, are immersed in the measured medium. For determining the electrolytic conductivity of the measured medium, the resistance or conductance of the space between the electrodes in the measured medium is determined. In the case of known cell constant, the conductivity of the measured medium can be ascertained from this determination.
In DE 10 2006 024 905 A1, an electrode arrangement of a conductive conductivity sensor is shown, in the case of which an inner and an outer electrode are isolated from one another and insulated relative to one another by a shaped seal and a seal support body. The shaped seal serves to prevent penetration of measured medium into an annular gap between the electrodes.
Such an electrode arrangement with additional seals is relatively complex from a constructive perspective. This is true especially for conductivity sensors which are intended for application in food technology or in the pharmaceutical industry. High hygienic requirements are placed on such sensors. For example, the probes of such sensors, insofar as they come in contact with the measured medium, are not allowed to have any difficulty accessible gaps. A cleaning and/or sterilizing of the entire probe surface, which contacts the measured medium, must be possible. Conventional seals or a shaped seal according to DE 10 2006 024 905 A1 can basically fulfill this purpose; however, they lead to a complex construction requiring a correspondingly complex assembly effort.